Exemplary embodiments of the invention relate to an optical sensor arrangement.
Optical sensor arrangements are, for example, used for the detection of pulsed laser sources that signal a threat. These lasers can be classified according to wavelength and radiation intensity:                Beamrider weapon systems, near infrared region (NIR)region, a few mW/m2 to a few W/m2 and        Target designators and rangefinders, 1064 nm, beam intensity up to a few MW/cm2.        
A saturation requirement is placed on laser detectors (which are intended to detect a radiation intensity of a few mW up to a few MW), that the sensor (detector) may not saturate, so that the dynamic range comprises at least 6 orders of magnitude. At the same time the detection of pulsed laser radiation requires high time resolution of the sensor. These requirements cannot be fulfilled with a single sensor that is known from the prior art, but sensor arrangements are usually selected that comprise two sensors S1, S2 disposed adjacent to each other with respectively associated entry windows F1, F2, wherein each individual sensor respectively detects only part of the desired dynamic range (FIG. 1).
If the sensor is also equipped with an optical arrangement in order to optimize the effective aperture of the sensor and the detected image angle, then each sensor is provided with a dedicated optical arrangement O1, O2. This increases the cost in terms of space and components for the design of a laser detector sensor.
U.S. Pat. No. 5,428,215 A discloses an arrangement comprising individual, parallel constructed channels for the detection of the dynamic range. The described sensor arrangement is known on the commercial market under the name HARLID®.
Sandwich diodes, which utilize the principle of the “vertical color filter detector group”, are known from U.S. Pat. No. 6,632,701 A. These detectors are commercially available in the combination Si/InGaAs. They comprise a plurality of stacked semiconductor layers with n and p doping, wherein the resulting respective p-n junctions form photodiodes. The individual photodiodes operate wavelength-selectively in different wavelength ranges. A similar design principle is disclosed by U.S. Pat. No. 7,683,310 B1 in the form of photodetectors disposed in series, wherein the individual detectors are designed for different wavelengths.
European patent document EP 0 236 035 A2 discloses a laser detector sensor, with which a plurality of linear detector arrays are disposed in the image plane of an imaging optical arrangement, which respectively monitor a strip section of the environment, wherein said strip sections are each at different distances from the sensor.
These arrangements are undesirable due to the limited dynamic range.
Exemplary embodiments of the invention are directed to a sensor arrangement with which the dynamic sensitivity is increased while maintaining the spectral wavelength range.
The optical sensor arrangement according to the invention comprises a sensor for the detection of electromagnetic waves and an aperture associated with the sensor, wherein at least two sensors disposed in series are provided for the detection of the electromagnetic waves entering through the aperture.
The at least two sensors disposed in series have matching spectral regions and cover the same region of the surroundings to be observed. The sensors are thus sensitive in coincident spectral regions. The sensors are exposed to radiation of the same wavelength but of different intensity.